optical illusion concave convex circles

navigate by keyword : abstract alike around art background bottom bulges bumps circles compare comparison concave convex craters dark different dimples effect equal fun funny graphic gray grayscale identical illusion illustration light magic optical pattern relief same shade shading shadow shadowed similar spheres surface texture textured top turn unequal vector visual white

Craters and bumps illusion. Concave and convex circles. Dimples with dark shading at the top, bulges with light shading at he top.